On my X-5000 I also get my mouse moving too fast from time to time (maybe 1 out of 5 reset) ! really annoying and a pity.

The only thing I can do is reset or disconnect/reconnect. Since I dont want to go behind the tower each time, I decided to plug a USB hub and connect the mouse to it, easier to disconnect on the desk rather than behind the tower laying on the ground under the desk...

how can you show how nice and shiny is your Amiga to someone when something like that happens ?

I've got a new KVM switch which features transparent keyboard/mouse emulation. This means all connected hosts see a permanently connected keyboard and mouse behind a USB hub.This works perfectly fine with one connected Windows10 and one connected Ubuntu 18.04.2 LTS machine.OS4.1FE Update 1 on the SAM440 is still unreliable. In about five out of 10 system startups either the keyboard or the mouse doesn't respond. I can get it to work by pulling the USB and plugging it back in a couple of times. But even then it sometimes looses the keyboard connection after half an hour or so.So I tried the debian-testing-sam440ep-CD from ACube's web site. Works like a charm! Booted 20 times in a row and each time the keyboard worked right from the start.This doesn't sound like a hardware issue to me.

So the question is: What's to blame? The OS4 low level driver or the rest of the protocol stack? And how can I find out?

Can I become involved in debugging that thing? Maybe compile it myself and try some fixes?

Found out the following:Both the mouse and the keyboard always show up in the USB inspector. But in the case one of them is not working it's because no driver was assigned to it."Driver: none"If I pull the USB plug (the one to the hub/KVM) a couple of times then sooner or later both of them will be assigned hid.usbfdThis sounds like a race condition and or timing issue to me.